google photos pop-ups

For the last couple of days, a really annoying popup has made Google Photos almost unusable, and I can't make it go away. It is four screens of stuff about what Google Photos can do, at it appears immediately when I open Photos, and I have to click through all four screens before I can see or do anything. And then it reappears anytime I click on a photo or try to do anything else. There is no apparent way to close it or to stop it from continually happening. This makes Photos impossible to use, as a practical matter. Why is this happening and how do I stop it? I contacted Google, who said it was a browser problem. Apparently it is, as this does not happen with Safari.

The same problem both in stable and Beta versions of Opera. Appeared approximately two weeks ago. No problem like this either in Safari or Chrome. Really annoying and impossible to use Google Photos. Looking forward to having it fixed asap.